The present invention relates to a photographic camerwa for three dimension photography and a method and apparatus for forming a visible three dimension reproduction of an image using lenticular screens.
Three dimension photography is known in which two photographs are taken from two different viewpoints and are separately viewed by both eyes. The two photographs are usually photographed simultaneously from two viewpoints spaced a predetermined distance apart using two photographic cameras juxtaposed, or a single photographic camera having two objectives. This type of photography is known as stereoscopic photography. Three dimension, using lenticular screens, is distinguished from the aforementioned in that a single photograph is used which may be three dimensionally viewed directly by both eyes. Three dimension using lenticular lenses is obtained by forming a plurality of images arranged in stripes of one and the same object as viewed through various angular positions through a lenticular screen. The lenticular screen has a plurality of lenses or optical elements successively connected to one another, each of these optical elements being in the form of a semi cylinder having a diameter as small as 0.1 mm to 5.0 mm.
In three dimension using lenticular screens, the photograph (positive) itself has a lenticular screen covering the surface of the photograph. The three dimension effect is obtained during viewing by a function of the lenticular screen and the image on the surface of the photograph when being viewed through the lenticular screen. When photographing a scene on the surface of a photosensitive material, the normal camera exposes the scene reversed, not only laterally but vertically. If a lenticular screen is placed in front of the photosensitive material during exposure for three dimensional purposes, individual images formed by the individual elements of the lenticular screen also present a laterally reversed position relationship in the overall reverse image and accordingly cannot be directly used as the image for three dimensional viewing. The reversed image formed by individual lenticular elements is referred to herein as a "reversed three dimensional image".
Measures have been taken to obtain the desired trivision image without the formation of the reversed three dimensional image. One proposed apparatus has a lenticular screen placed in front of a photosensitive material which is moved synchronously with movement, over a desired distance, of a shutter or a slit adapted to move across an objective by unit width of said reticular elements in photographing and thereby an object image which would otherwise be projected as the corresponding reversed three dimensional image is projected as a corresponding normal three dimensional image.
Another proposed apparatus provides a mask (screen) with a slit interposed between a lenticular screen and photosensitive material. The mask is moved relative to the photosensitive material for the time duration of a single shutter opening. The amount of movement of mask and photosensitive material is selected from multiples of a unit width of the lenticular elements. As a result a reversed three dimensional image is convert4d into a normal three dimensional image.
Either of the aforegoing proposed apparatus eliminates the inconvenient operation usually essential to obtain a directly viewable three dimension image.
In the usual apparatus an object to be photographed or the camera itself is rotated in a circular arc while repeated exposures are made of the same object. With this arrangement the desired directly viewable three dimension image is obtained by a single photographing operation. However, such apparatus requires the synchronous movement of the lenticular screen for each scanning during which the shutter is moved across the objective and the relative synchronous movement, among the lenticular screen, the mask provided with the mask, and the photosensitive material. As a result, these apparatus are not suitable for photographing moving objects nor for momentary photographing using a strobe light or flash in which the emission period is shorter than the period of movement of the respective members. Also, this results in a camera of too high a cost to be commonly used and the camera and equipment parts would not be easy to carry.